Sound Transit’s East Link Extension Project is featured in the Popular Science magazine as one of the 100 greatest innovations of 2017. The project involves extending light rail transit (LRT) from Seattle to Bellevue, WA, on the Homer M. Hadley Floating Bridge (WSDOT I-90). When the Extension opens for service, it would be the world’s first LRT operation on a floating bridge. One of the biggest challenges is how to safely transition light rail trains, operating at up to 55 mph, from the land-based bridge structure to the floating bridge. This challenge is addressed by an innovative “track bridge” system consisting of curved steel platforms and multiple sets of bearings that can accommodate movements of the floating bridge on Lake Washington.

As noted by Popular Science, the bridge is scheduled to be completed in 2023 and, by 2030, it is projected that 50,000 train riders a day will commute via the East Link Extension.

As part of the track bridge design team, SC Solutions’ involvement in the project included development and analysis of 3D detailed finite element models to assess behavior and performance of track bridge concepts under dynamic loads. Analysis cases included consideration of the full bridge/pontoon/train coupled system to evaluate train accelerations, rail stresses, and other response quantities. SC Solutions’ analysis significantly contributed to the verification of the track bridge design to meet Sound Transit’s operational (train speeds, passenger comfort, etc.) and safety requirements.